Inquiry (采购产品): cleaning outside of ducts I have metal (probably tin) heat/air conditioning ductwork on the ceiling in my basement. It has greasy looking dark spots, maybe some are scratches. I tried, all purpose cleaners such as Simple Green, stainless steel wipes, and silver polish. None have made any difference. Is there anything I can try to improve the smudgy look of the outside of these ducts. Thank you Stella Gruenbacher Wichita, KS nonallegra@cox.net **** Hidden Message ***** Stella Gruenbacher 67203 USA Company: hone E-mail: nonallegra@cox.net **** Hidden Message ***** nonallegra@cox.net